package com.atguigu.yygh.user.utils;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class IpUtils {
    private static final String UNKNOWN = "unknown";
    private static final String LOCALHOST = "127.0.0.1";
    private static final String SEPARATOR = ",";

    public static String getIpAddr(HttpServletRequest request) {
        System.out.println(request);
        String ipAddress;
        try {
            ipAddress = request.getHeader("x-forwarded-for");
            if (ipAddress == null || ipAddress.length() == 0 || UNKNOWN.equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getHeader("Proxy-Client-IP");
            }
            if (ipAddress == null || ipAddress.length() == 0 || UNKNOWN.equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getHeader("WL-Proxy-Client-IP");
            }
            if (ipAddress == null || ipAddress.length() == 0 || UNKNOWN.equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getRemoteAddr();
                if (LOCALHOST.equals(ipAddress)) {

                    InetAddress inet = null;

                    try {

                        inet = InetAddress.getLocalHost();

                    } catch (UnknownHostException e) {

                        e.printStackTrace();

                    }

                    ipAddress = inet.getHostAddress();

                }

            }

// 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割

            // "***.***.***.***".length()

            if (ipAddress != null && ipAddress.length() > 15) {

                if (ipAddress.indexOf(SEPARATOR) > 0) {

                    ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));

                }

            }

        } catch (Exception e) {

            ipAddress = "";

        }

        return ipAddress;

    }

}